Conventionally, in various industrial fields, bonding substrates such as plastic films, vapor deposition films, metal foil, paper, and nonwoven fabric by heat pressure (that is, heat sealing) has been known. In heat sealing, generally, an adhesive layer is formed on the substrate in advance, and these substrates, or the substrate and another adherend are bonded with an adhesive layer interposed therebetween.
For the materials used in such heat sealing, a heat sealing material have been proposed. The heat sealing material includes a heat sealing adhesive composition and a substrate on which the heat sealing adhesive composition is applied. The heat sealing adhesive composition includes an emulsion in which resin particles are dispersed in water, and the resin particles contain olefinic polymer (A) and acrylic polymer (B) in the same particle. To be more specific, Patent Document 1 below proposed the following: a heat sealing adhesive composition is produced by polymerizing 55 parts of methylmethacrylate and 1-butylacrylate in the presence of 150 parts of polyolefin emulsion, and after the produced heat sealing adhesive composition is applied on paper and dried, the applied surfaces are subjected to heat sealing.